The US Chemical Safety Board (CSB) will pursue a full
investigation to determine the causes of
last weeks fire at the 245,000 bpd Chevron refinery
in Richmond, California, the agency announced on Monday.
A CSB team with seven investigators arrived at the refinery last Wednesday and has
since been conducting witness interviews and reviewing
documents at the site.
CSB structural and industrial safety experts will arrive at
the site later Monday to prepare for safe entry by
investigators into the immediate area of the fire, the agency
The fire occurred when a combustible hydrocarbon liquid known as
gas-oil leaked from an eight-inch pipe connected to
a crude oil distillation tower in the refinerys crude unit.
Workers initially noted the leak and were in the process of
attempting repairs on piping connected to the still-operating
crude oil distillation tower when the leak
Due to the high temperature of the material in the tower, in
excess of 600 degrees Fahrenheit, the gas-oil immediately
formed a large flammable vapor cloud.
Witness testimony collected by CSB investigators
indicates that a large number of workers were engulfed in the
vapor cloud, said CSB team lead Dan Tillema, P.E.
These workers might have been killed or severely
injured, had they not escaped the cloud as the release rate
escalated and the cloud ignited, shortly thereafter.
CSB chair Dr. Rafael Moure-Eraso called the fire a
near-disaster for refinery personnel.
The circumstances warrant a full and independent
federal investigation to determine the root causes, Dr.
Moure-Eraso said. Although fortunately no workers were
killed, the overall impact of the incident ranks it as among
the most serious US refinery incidents in recent
CSB board member Mark Griffon, who accompanied the
investigators, said information gathered so far indicates the
incident had a serious impact on the community.
Area hospitals told CSB investigators that they
attribute hundreds of emergency room visits by community
members to reported effects of the release and fire, with
symptoms ranging from anxiety to respiratory
Mr. Tillema said important issues in the investigation
include understanding why the pipe that later failed was kept
in service during a late 2011 maintenance turnaround and what
procedures and industry practices exist for responding to a
leak of combustible material from a running unit.
He said the CSB anticipates executing a site preservation
and evidence testing agreement with Chevron and other
investigative groups and arranging for independent testing of
the leaking section of pipe to determine the failure
Both Chevron and the United Steelworkers, which represents
hourly workers at the plant, have been cooperating with the CSB
team, the agency said.
Chevron has provided assurances its personnel will freely
share their knowledge and investigative information with the
Cal/OSHA, Contra Costa County, the US Environmental Protection Agency, and
other investigative groups are also fully cooperating,
according to the agency.